Oil prices edged lower on Wednesday after government data showed U.S. crude oil stockpiles rose unexpectedly last week, prompting investor concerns of excess supplies.
Brent crude futures fell 40 cents, or around 0.6%, to $66.23 a barrel by 12:04 p.m. EDT (1604 GMT). U.S. West Texas Intermediate crude slipped 33 cents, or 0.52%, to $63.34.
Both benchmarks, which traded close to their highest in two-weeks in the previous session, fell after data from the Energy Information Administration showed crude stockpiles rose by 3.5 million barrels to 441.8 million barrels last week.
Analysts in a Reuters poll had expected a 1.1 million-barrel draw.
Net U.S. crude imports rose last week by 422,000 barrels per day, the EIA said.
API industry data also showed a large build of 4.3 million barrels in crude stocks last week, market sources said on Tuesday.
"Definitely, the crude build in the API numbers was not of help," UBS analyst Giovanni Staunovo said of Wednesday's oil price fall.
The Organization of the Petroleum Exporting Countries and allied producers, known as OPEC+, has been increasing supply to the market.
On Wednesday, however, OPEC trimmed its forecast for growth in oil supply from the United States and other producers outside the wider OPEC+ group this year.